Atoms, molecules, elements, compounds, substances, mixtures
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Transcript of Atoms, molecules, elements, compounds, substances, mixtures
Atoms and Molecules
Elements and Compounds
Substances and Mixtures
Atoms
➲ The simplest particles that make up matter
➲ Represented by balls
Molecules
➲ Molecules are made when two atoms are attracted to each other with strong forces and bond
➲ When two or more atoms join together to make a molecule, it is called a chemical reaction
Elements
➲ Elements are substances formed by atoms of a single type
Elements cannot be broken down into more simple substances
➲ There are three kinds of elements: Atomic elements Molecular elements Elements with a crystal structure
Compounds
➲ Compounds are substances formed by different atoms, always combined in fixed proportions
They are represented by formulas formed by the symbols of their elements and subscript numbers which indicate the number of atoms of that element in the compound
CO2
➲ Two types of compounds Molecular compounds Compounds with a crystal structure
1)Pure substances
Formed by similar particles
➲ Homogeneous mixture/solution: when we cannot differentiate between their components
Sea water, air
➲ Heterogeneous mixture: when we can distinguish the components of the mixture
Granite rock
2)Mixtures
Substances and Mixtures
➲ Pure substances are formed by similar particles (atoms or molecules)
Most of the matter that we see is a mixture of substances
➲ The main difference between pure substances and mixtures is that the first have well definied specific propertires: density, fusion and boiling temperatures, while mixtures do not